U.S. Pat. No. 4,722.273 discloses an internal combustion engine with at least two power adjusting elements which are electrically driven independently of each other. In engines of this kind, different torque contributions of the cylinders occur and the air supply of these cylinders is supplied via different power adjusting elements. This is caused by different charges of the cylinders because the supplied air mass flow is, inter alia, dependent upon the geometry of the power adjusting element (the throttle flap) and/or the different characteristic lines of the actual value transducers of the power adjusting element (potentiometers of the throttle flap) in so-called electronic gas-pedal systems. The different cylinder charges and therefore the different torque contributions lead, however, to an operating performance of the engine which is not completely satisfactory.
It is an object of the invention to provide measures which facilitate an equalization of the individual cylinders.
The method of the invention is for synchronizing at least two power-adjusting elements of an internal combustion engine, the engine including at least first and second power-adjusting elements controlled electrically independently of each other, the first power-adjusting element adjusting the air supplied to at least a first cylinder of the engine and the second power-adjusting element adjusting the air supplied to at least a second cylinder of the engine. The method includes the steps of: determining a quantity representing the deviation of the torque contributions of the cylinders, respectively; carrying out a correction of the position of at least one of the power-adjusting elements on the basis of the quantity to effect a reduction of the deviation; and, adjusting the power-adjusting elements while considering the correction.
A procedure is provided with which the equalization of cylinders or cylinder groups takes place in a simple manner and whose air supply is influenced by power adjusting elements controlled electrically independently of each other. It is a special advantage here that different torque contributions of the cylinders are reduced or avoided with the application of this procedure as a consequence of different charges because of different geometries and characteristic lines in the region of the power adjusting elements.
It is especially advantageous that the equalization is undertaken on the basis of the time-dependent or angular distance of two ignitions of the affected cylinders so that the consideration of additional quantities such as the intake manifold pressure on the cylinders, the air mass flows to the cylinders, et cetera, is not required.
It is especially advantageous that, with a mutually opposing adjustment of the power adjusting elements, a rapid precise correction takes place and therefore the equalization is reliably established.
Especially advantageous is therefore the use in systems wherein no separate air masses are measured and wherein no separate intake manifold pressure data are present. This is especially the case in sport engines having high power so that the described procedure presents special advantages in this area of application.
It is especially advantageous that the equalization of several cylinders is significantly improved and that, in this way, additional further influences on the torque of the individual cylinders can be compensated with these influences being caused by non-uniform compressions, non-uniform air/fuel composition, unequal valve strokes, et cetera.
In an advantageous manner, the synchronization takes place in the context of a separate synchronization operation but also as an adaptation method during the running operation of the vehicle equipped with the engine.